The present invention relates to a picture display apparatus producing pictures by means of a sequence of lines, provided with user-accessible means for the simultaneous control of the line length and the vertical spacing between the lines.
Such an apparatus is, for example, a television receiver or a television monitor.
An apparatus of this type is disclosed in the U.S. Pat. No. 2,510,670 (Barnet S. Trott), which describes a television set having means for increasing the vertical amplitude and the horizontal amplitude together and in the same ratio so as to create a so-called "zoom" effect.
This apparatus does however not solve a different problem, namely the problem that: there are now television receivers on the market designed for receiving pictures whose width/height ratio, denoted aspect ratio, is 16/9. These pictures are transmitted more specifically by television satellites. In contrast thereto, the majority of television transmissions nowadays have an aspect ratio of 4/3.
When the reception of a picture having an aspect ratio of 4/3 on a television receiver having an aspect ratio of 16/9 is involved, it is sufficient to take measures to reestablish the correct aspect ratio of the picture and in addition the user wants to have the option to choose between the loss of a portion of the received picture or the fact that he cannot use the entire surface of the screen; this will be described in greater detail hereinafter with reference to the Figures. In high-gamma receivers, having an aspect ratio of 16/9 or an aspect ratio of 4/3, provided with picture stores allowing complex digital processing of the pictures, the pictures can be manipulated at will in order to solve all the above-mentioned problems.